Marking out tools ppt

Done by: G. Tulloch

Marking out is the process of transferring a design, layout or dimensions from the drawing to a work-piece, and it is considered as the first step in the manufacturing process. The tools used to do such activities are called marking out tools.

• Some of the marking tools used in metal work include but not limited to are:

• Scriber• Marking blue• Punches• Engineer’s square• Surface plate• Surface gauge• Angle plate• Vee block• Steel rule• Dividers• Ball peen Hammer

• A Scriber is used to mark the surface of Metal and Plastic and gives a fine, accurate line.

• The mark is scratched into the surface of the material and CANNOT BE REMOVED.

• To avoid the surface of the material being scratched, a Scriber can be used after a coat of Marking Out Fluid has been applied to the material.

Marking blue is a dye used in metalworking to aid in marking out.

It is used to paint a metal object with a very thin layer of dye that can be scratched off using a scribers to show the bright metal underneath.

The punch is a hard metal rod with a shaped tip at one end and a rounded butt at the other end, which is usually struck by a hammer.

They different type of punches: Centre punch Dot punch Pin punch

It is used as an aid to drilling operations. The center punch forms an indent in which the tip of the drill fits. A center punch has a point angle of 90°.

It is used to produce a smaller indentation than a center punch, which acts as a useful datum (standard) point in layout operations. A dot punch has a point angle of 60°.

The engineer’s square is used for checking the straightness of a work piece. It can also be used for marking perpendicular lines onto a work piece.

The surface plate has a high degree of flatness. The flat surface is being used as a datum surface for marking out and for measuring purposes. It is also called surface table if it can stand on the floor.

A surface gauge is used on surface plates for scribing lines on work pieces and checking parallel surfaces and heights.

• The angle plate is used to assist in holding the work piece perpendicular to the table. The angle plate is provided with holes and slots to enable the secure attachment, clamping and adjusting of work pieces.

The Vee blocks are generally used for holding circular work pieces for marking out or machining.

• Steel rules are made from Carbon or Stainless steel.

• The most common sizes are either 300mm or 150mm.

• They should be used for measuring when marking out and NOT for drawing straight lines.

• The spring divider is used for scribing arcs or circles. The below figure shows a circle that was marked by a spring divider onto a work piece.

• The ball-peen hammer is shown in the figure. The crowned, or rounded, edge (hemispherical head) works metal smoothly without marking it. The other end of the hammer can be used to strike punches and chisels